A substantial insider sell was reported on October 9, by Mona Chu, Chief Accounting Officer at Pure Storage (NYSE:PSTG), based on the recent SEC filing. What Happened: According to a Form 4 filing with the U.S. Securities and Exchange Commission on Wednesday, Chu sold 20,647 shares of Pure Storage. The total transaction value is $1,063,320. At Thursday morning, Pure Storage shares are down by 0.64%, trading at $52.82. Discovering Pure Storage: A Closer LookPure Storage Inc is a U.S.-based company that provides an enterprise data storage platform that transforms business through a dramatic incr…